Just a few miles inland from the super-sleek international resort of Saint Tropez lies a treat of a medieval village with streets built up a hillside in ever-decreasing circles, like the shell of a snail. At the centre of Ramatuelle’s spiral, in part of an ancient chateau, stands a hidden house which for the past five years has been home to Marjolaine Leray, her husband, Claude Avignon, and her daughter, Mia, now aged 12.

Not content with transforming a large building that had lain empty for more than 50 years, she has also, with her business partner and best friend, Sitor Senghor, opened three shops selling artefacts from around the world. La Galerie des Matières is in her own vaulted cellar, formerly home to one of the village’s three olive presses. Thanks to the hill’s incline, this 'basement’ is sited at street level (conversely, the garden at the back is higher than the street). La Salle du Château, which houses a cabinet of curiosities and a fabric workshop, is in the next-door building, which used to be part of the 17th-century chateau. The third shop is a tiny boutique, ALM25, filled with ceramics, lamps and paintings.

Finding Leray in this small-town environment is something of a surprise. She is an international decorator, and her company, ALM, began as a consultancy with her husband as the architect-designer, and Senghor as the art expert. They have been in demand ever since, creating houses, hotels, shops and restaurants in France, Italy, Spain, Switzerland, England and America. The architectural practice is now housed above ALM25. Leray usually works in a friendly, contemporary style, stating, 'I like to show that modern can also be warm.’ However, once in a while she is seduced by an old house. That is what happened here.

In fact, moving here was something of a homecoming for Leray, who was born and brought up in Ramatuelle. She left at the age of 12 to go to boarding school, and has since lived around the world, in New York, Paris and London among other places. Although she had happy childhood memories of the place, Leray had no plans to move back . But when she heard that the 'large house of the village’ was for sale, she couldn’t resist looking round.

She found it in ruins but 'charming because it somehow felt right and like the family house I’d always dreamed of. I could not believe my dream house was also in my dream village,’ she says. Pleasing features included a tangled garden hung with vines, a view of the sea from the top floor, and an external metal staircase designed in 1868 by Gustave Eiffel’s company, which had made it possible to add two floors. Amazingly, as Leray says, 'You can’t see the house from the village; it is higher than the street and tucked away.’

It required rather more than a lick of paint to become habitable again. The previous owner had lived in one room, and there were trees growing inside. Moreover, the kitchen was in a corridor, there was only one bathroom, and the lavatory was in the garden. It was clear that the whole exercise would be long and challenging. The narrow, spiralling streets made it difficult to bring in the heavy machinery required, while the beams were so long it took imagination and planning to get them through Ramatuelle at all.

First the basic structure had to be shored up and given a new roof (curved like the original), and the lofty stone cellar was restored. In order to put in under-floor heating the ground-floor tiles were taken up and replaced with hexagonal ones, and chestnut floors were installed everywhere else (none of the other levels had floors at all).

The chateau was never home to a grand seigneur, so was built of plain materials – stone instead of marble, and local walnut or chestnut instead of oak. Fortunately Avignon is 'crazy about wood and natural materials, and although I studied wood engineering he knows so much more than I do about it,’ Leray says. Twenty years ago he started a woodworking company that makes what he designs, from full-size residential to tree houses. The company owns a large stock of aged wood for furniture and floors.

'When we work for ourselves it’s more difficult, because we always come last,’ Leray explains. Nevertheless, the whole renovation and decoration took only nine months. Avignon designed the handsome wooden-cupboard-lined kitchen, the bathroom’s wood walls (and mirrors and basin tables), and found old doors to replace missing ones (more than half of them) along with the kitchen and living-room tables. The old fireplaces remained, some inset with different stones.

Leray and Avignon initially planned a modern interior, but ended up keeping as many original features as possible. They furnished with a mix of simple antiques (leather armchairs, painted chests, work by artists such as Francine Demeulenaere and objects gleaned from around the world – a row of Chinese baskets on high in the kitchen and spindly Vietnamese sculptures in the bedroom. The walls are painted in traditional limewash.

Leray’s two larger shops have even more soaring proportions and theatrical furnishings than the house. La Galerie des Matières is full of 'textures – wood, iron, salt balls that look like stone, Zulu hats made from hair, glazed sculptures from Asia, carpets made in Turkey,’ as Leray puts it. Some items are old, some new, like the photographs by Mark Luscombe-Whyte, who took the pictures for this article. The several levels of La Salle du Château house quantities of 18th-century Swedish, French and Italian furniture and a room full of old and unusual fabrics, such as Sabina Fay-Braxton’s velvets.

Leray loves the house for being a wonderful family home and for the business adventure it has triggered: house, shops and architecture studio are next to each other . It is only five minutes from Saint Tropez, but beach culture is entirely absent. Instead Leray’s emporium is a tempting vision of things beautiful and rare.